The present invention relates to dispensers for supplying sheets of material, such as tape flags and/or paper notes, from coherent stacks of such sheets. The invention is particularly related to such dispensers that hold and supply sheets from a plurality of stacks of flexible sheets.
The art is replete with dispensers for supplying sheets of material that are adapted to mark portions of substrates such as written documents. Sheets from Post-it® brand flag and note pads available from 3M Company are used extensively as such sheets, and are particularly useful for that purpose because a repositionable pressure sensitive adhesive with which they are coated allows them to be placed on and removed from a document without damage to the document. A wide variety of such sheets are available to suit various needs and purposes of the user. For example, in addition to having different sizes and colors, some sheets are made of paper, while other sheets are made of a polymeric material; some sheets are opaque, so as to allow the user to write a message on the sheet, while other sheets are substantially transparent to allow easy viewing of the document to which the sheet is attached; and some sheets have a large percentage of the surface coated with adhesive, while other sheets have only a small percentage of the surface coated with adhesive.
The variety of such sheets has resulted in a similar variety of dispensers, because the dispensing characteristics of the sheets also vary with, for example, sheet size or shape, type of sheet material, amount and location of adhesive on the sheet, and so on. The dispensers are typically optimized for dispensing a particular type of sheet (for example, polymeric sheets having a majority of one surface coated with adhesive, or paper sheets having only a narrow strip of adhesive on one surface). Dispensers tend to be either (1) of the type in which the bottom sheet of the stack of sheets is attached to the bottom of the housing or the stack is otherwise restricted from significant movement in the housing, and the sheets are dispensed through a fairly wide slot as is taught in U.S. Pat. No. 5,769,270 Fujisawa et al., or (2) of the type in which the stack of sheets is free to reciprocate or shuttle in the housing as the sheets are dispensed, and the sheets are dispensed through a rather narrow slot as is taught in U.S. Pat. No. 4,907,825 to Miles et al.
A user may desire or have need to use sheets of more than one type (e.g., sheets of different colors, sizes, and/or materials). Accordingly, dispensers for use with multiple stacks of sheets are known. However, presently available multi-stack dispensers have deficiencies. For example, multi-stack dispensers using a “shuttling” action to dispense individual sheets are segmented into multiple slots or compartments with each slot or compartment containing a single stack of sheets to allow independent movement and maintain lateral spacing of the stacks. Such dispensers are complex to form and do not lend themselves well to automated assembly. In addition, multi-stack dispensers are typically designed for stacks having sheets with a common construction (e.g., the same sheet material, amounts of adhesive, sizes, etc.) and use the same method of dispensing (e.g., shuttling movement or restricted movement), and are not suitable for use with stacks having sheets with different constructions or requiring different methods of dispensing.